TWO car bombs killed at least 46 people in Mumbai overnight, one ripping through a congested market and a second exploding near a popular tourist attraction.

A bombed car lies next to the Gateway of India / AP

Police were focusing their investigation on Muslim militant groups - though victims from the explosions were almost certain to include both Hindus and Muslims.

No one immediately claimed responsibility for the bombings, which came hours after the release of a long-anticipated archaeological report on a religious site in northern India claimed by both Hindus and Muslims. The dispute has been linked to previous bombings.

The bombs were hidden in the trunks of two taxis and exploded within five minutes of each other, police said. Several people were being interrogated, including one taxi driver.

"There are many jihadi groups out, let loose by the enemy country," said Ranjit Sharma, a police commissioner. Jihadi groups are operated by Islamic militants.

He specifically mentioned the Students Islamic Movement of India (SIMI), a militant Muslim students' group outlawed in 2001, and Lashkar-e-Tayyaba, one of more than a dozen Islamic rebel groups fighting Indian security forces in Kashmir since 1989.

His mention of an "enemy country" was a clear reference to Pakistan, India's long-time rival, though Pakistani officials quickly denounced the attack as "wanton targeting of civilians".

Police said there was no direct evidence linking those groups, or Pakistan, to the bombings.

The attacks appeared aimed more at the city itself than at members of a particular religion.

Popular spots

One of the bombs exploded at the Gateway of India, an historic landmark and tourist attraction built by India's former British colonizers to commemorate the 1911 visit of King George V.

The massive arch is often host to outdoor concerts and is a popular lunchtime eating spot for both Hindus and Muslims. The other blast was at a crowded neighbourhood of jewellry stores, where many shops are owned by Hindus but where many of the artisans are Muslims.

"All kinds of people work here - Hindus, Muslims and Christians," said Ali Asghar, 24, a student whose father works in a bank near the jewellry market. "This is not about religion."

But his father feared Muslims would be blamed.

"I don't want to leave Mumbai. Where would we go? We feel safe here," said Mohammed Asghar.

Sushil Kumar Shinde, chief minister of Maharashtra, the state where Mumbai is located, said the explosions had targeted the city's economy.

"The blasts have thrown up a challenge to the resilience of this city," he told a news conference, urging people not to panic.

Telephone lines were jammed and mobile phone services briefly crashed as panicked residents called family and friends.

Pakistan sympathy

Pakistan, with whom India has engaged in decades of bloodshed, condemned the attacks.

The neighbours have fought three wars - two over the divided region of Kashmir - and nearly started a fourth last year. New Delhi accuses Pakistan of supporting militants in Kashmir, which Islamabad denies.

"We deplore these attacks and we sympathise with the victims and their families," Pakistan Foreign Ministry spokesman Masood Khan said.

"I think that such wanton targeting of civilians should be condemned in the strongest possible terms."

UN Secretary General Kofi Annan "utterly condemns the terrorist bomb attack ... (and) conveys his heartfelt condolences to the Government of India and the bereaved families of the victims of these despicable acts of terrorism," UN deputy spokeswoman Hua Jiang said in New York.

'Body parts'

The carnage shocked even to those accustomed to bloodshed.

"I have never seen anything so horrible," said S. Manoj, a doctor at Mumbai's J.J. Hospital. "It was just body parts, some with their abdominal organs hanging out, some with no faces at all. The bodies were all burnt."

Manoj said some of the injured had been trampled in stampedes after the explosions, and came in with multiple broken bones.

The explosion terrified Mumbai residents.

"I rushed out and saw the crowds at the Gateway of India. ... We saw some body parts lying around, before we were told to move away by the police," said Ingrid Alva, a public relations consultant who works near the landmark just next to the century-old Taj Mahal Hotel, where some windows were broken.

Still, the city quickly turned out to support the victims. More than 100 people donated blood for the wounded at J.J. Hospital.

Religious motive

The explosions came just hours after the release of the archaeological report on the religious site in the northern Hindu holy town of Ayodhya.

In March, a bomb attack on a Mumbai train, which police blamed on Islamic militants, killed 11 people and wounded 64 others.

That explosion came a day after the 10th anniversary of a series of bombings in Mumbai - also blamed on Islamic militants - which killed more than 250 people and injured 1000.

Police say those bombings were in retaliation for the 1992 destruction by Hindu mobs of the 16th-century Babri Mosque in Ayodhya, and to avenge Muslim deaths in riots that followed.

A bloody attack on Hindus who want to build a temple at the site of the destroyed mosque set off revenge rioting in western Gujarat state that killed more than 1000 people, mostly Muslims, in early 2002.

Some Hindus claim the mosque was built centuries ago on the ruins of a Hindu temple that marked the birthplace of their supreme god, Rama.

The report, issued by government archaeologists, indicated there had been an ancient structure at the site, lawyers for both sides said, though they disagreed on whether it said there had actually been a temple.

The report was released to lawyers but has not been made available to the public or the media.